   (-contains-key? [coll k]
     (obj-map-contains-key? k strobj))
 
-  IKeyed
-  (-contains? [coll k]
-    (-contains-key? coll k))
-  
   IMap
   (-dissoc [coll k]
     (if (and (goog/isString k) (.hasOwnProperty strobj k))

    (and
     (set? other)
     (= (count coll) (count other))
     (every? #(-contains? coll %)
             other)))

  IHash

  (assert (= #{} (-empty #{1 2 3 4})))
  (assert (= (reduce + #{1 2 3 4 5}) 15))
  (assert (= 4 (get #{1 2 3 4} 4)))
  (assert (contains? #{1 2 3 4} 4))
  (assert (contains? #{[] nil 0 {} #{}} {}))
  (assert (contains? #{[1 2 3]} [1 2 3]))
  (assert (not (contains? (-disjoin #{1 2 3} 3) 3)))
  (assert (neg? -1))
  (assert (not (neg? 1)))
  (assert (neg? -1.765))
